The invention relates, in general, to movable barrier operators and, in particular, to garage door operators having systems for receiving radio frequency transmissions that are encoded or encrypted to identify an authorized user of one or more transmitters.
A number of systems already exist for the control of movable barrier garage door operators using radio frequency transmitters. For instance, U.S. Pat. No. 4,750,118 discloses a transmitter for transmitting a multiple bit code which, when received and decoded by a receiver, causes the receiver to command a motor to open or close a garage door. Other systems, such as that disclosed in U.S. Pat. No. 3,906,348, employ a transmitter and a receiver wherein a plurality of mechanical switches may be used to establish a stored authorization code.
U.S. Pat. No. 4,529,980 to Liotine et al. discloses a transmitter and receiver combination for use in a garage door operator wherein the transmitter is able to store an authorization code which is to be transmitted to and received by the receiver over a radio frequency link. In order to alter or update the authorization code contained within the transmitter, the receiver is equipped with a programming signal transmitter or light emitting diode that can send a digitized optical signal back to the transmitter where it is stored. Other systems employing coded transmissions are disclosed in U.S. Pat. Nos. 4,037,201, 4,535,333, 4,638,433 and 4,988,992.
While each of these systems has in the past provided good security for operational use, they are relatively inconvenient or insecure for a user who wishes to establish a new fixed code for storage in a receiver. Many of the currently-available garage door operators include equipment that enables the receiver to learn a particular code. However, they are relatively inconvenient to use because they must be accessed by pressing a learn code button located on the head unit of the receiver which, of course, is normally mounted from the ceiling of the garage. Thus, the user would have to climb a step ladder, push the learn button and then either send newly encoded signals from an outside keypad or from a transmitter. If the apparatus does not employ an actuator which would cause a door to be moved, but relates, for instance, to an automotive security system, the learn button of necessity must be made even more inaccessible than the learn button on a garage door operator. For instance, an auto security system learn button might be positioned someplace under-neath a locked hood or the like. Thus, it is very inconvenient, due to security requirements, to obtain access to the learn button.
What is needed then is an improved movable barrier operator or other type of actuator system employing coded transmissions which provide good security while enabling a code to be easily and conveniently altered.
The invention relates, in general, to an apparatus for controlling an actuator in response to receiving a coded transmission. The apparatus includes a portable radio frequency transmitter, a fixed radio transmitter, such as a keypad device, a wired control device connectable via direct wire connection, all connectable to a head unit or other actuator device. The system includes means for learning a new code from a transmitter or learning a new code from a fixed keypad having an RF transmission system. In the event that the fixed keypad is employed, the operator typically has an alphanumeric keyboard associated with the keypad having keys. A code may first be entered which allows the person to have access. This code is then followed by a learn authorization code which, for instance, may be 0000 or some other easily remembered combination of alphanumeric characters. At that point, the head unit authorizes receipt of a new code. The new code is then typed in on the alphanumeric pad of the keypad and is received by the head unit and stored therein as a new code from which to respond.
In an alternative mode of operating the code learning system, a radio frequency transmitter or the like may be used to enter a code which is to be stored within a receiver in the head unit. If such a radio frequency transmitter is to be used, the security to prevent unauthorized changing of the transmitter code is achieved through the use of the control pad which is located on the inside of the garage. The light switch for the control pad is held down and as it is held down, the command switch is actuated. The combination of the command signal and the light or work light signal is received by the head unit and the head unit then switches into a learn mode. The radio frequency transmitter must be up and transmitting a code at the time that the command button is pushed so that a code is immediately received by the antenna of the head unit. The code will then be stored in the receiver associated with the head unit and, from then on, actuation of the transmitter having that code stored therein will cause the garage door operator to be actuated. Thus, it is apparent that the system provides high security requiring the entry of a code or access to a secured area. Access is restricted to authorized users by either forcing the user to enter the work light followed by the command keystroke on the interior pad for which one can only obtain access if they have a key to the garage or a transmitter which can open the garage door with an already authorized code. Authorization is provided in the alternative by allowing access through the keypad on the outside of the garage door, but requiring that a code that matches one of the authorization codes already stored in the head unit be entered manually before the system even can accept a learn command. It may be appreciated that although the system may still include a learn button mounted on the head unit as a fail safe for reprogramming of the garage door operator, the ability to reprogram either directly from the RF keypad mounted on the outside of the garage or by using the inside wired control allows rapid and easy reprogramming without subjecting the user to the inconvenience of having to actuate the learn button on the head unit.
It is a principal object of the present invention to provide a code driven apparatus having a secure yet simple system for allowing learning of a code from a radio frequency transmitters
Other objects of this invention will become obvious to one of ordinary skill in the art upon a perusal of the following specification and claims in light of the accompanying drawings.